1. Field of the Invention
The present invention relates generally to catheters for use in medical applications such as hemodialysis wherein fluids are withdrawn and/or introduced into a cavity of the body. The invention relates particularly to a hemodialysis catheter having internal means to automatically stop blood flow after a dialysis procedure has been conducted.
2. Description of the Prior Art
Hemodialysis is a process of mass transfer in which certain chemical substances accumulated in the blood because of kidney failure are transferred from the blood across a semipermeable membrane to a balanced salt solution in a dialysis machine. In a typical hemodialysis procedure, a double-lumen catheter is utilized to simultaneously withdraw blood from a body cavity through one channel or lumen for processing in a dialysis machine and to reintroduce the processed blood back to the patient through a separate lumen.
Such catheters typically include a catheter hub or branch connector for connecting the catheter to tubes leading to and from a dialysis unit. The hub or connector may also be adapted for accommodating injection syringes, or other extracorporeal equipment which may be required for a selected medical procedure. To facilitate connection of the catheter hub to such equipment, the hub typically includes extension tubes which accommodate clamps for opening and closing the fluid passage ways of the respective extension tubes. The clamps serve as on-off valves for controlling the flow of blood between the catheter and dialysis unit or other medical equipment. Typical dialysis catheters are shown in U.S. Pat. No. 5,197,951 and U.S. Pat. No. 5,486,159 both to Mahurkar.
The requirement of extension tubes and clamps to prevent blood flow after a dialysis or other medical procedure has been conducted, makes conventional dialysis catheters somewhat cumbersome and uncomfortable for the patient. Manual operation of the clamps also requires additional manipulation by the dialysis professional to complete the procedure. The external clamps are also prone to tampering and inadvertent opening or loosening.
Accordingly, it would be desirable to provide a small, light-weight catheter which reduces the discomfort to the patient and is also automatic in nature thereby reducing the manipulation required by the dialysis professional to complete the procedure.